Commissioner Winton said he had become concerned about how much space the buildings would take from parkland and the amount of public funds needed for construction costs. He said although he supports the creation of a ‘museum park’ he wants to clarify both issues before he will lobby fellow commissioners for support. Bicentennial Park lies within Mr. Winton’s district.

"The principal issue in my mind is related to the difference between the buildings’ footprints and the land they need for the sculpture parks," he said. "They need to show the public how both things differentiate from each other. The outside portion will become part of the landscaping fabric of the park."

He plans to ask commissioners in May to consider allowing the museums to move to the waterfront park near downtown Miami, Commissioner Winton said Tuesday. So far, commissioners have welcomed the concept, conceived a year ago through public meetings. In all, three proposals emerged and were presented to the commission but nothing has been approved.

Each group proposes a 4-acre building next to 4 outdoor acres for sculptures and exhibits. Together, the museums would occupy 16 of the park’s 29 acres.

Those are the numbers that drew some concern last week from park advocates who want to preserve green space.

Ms. Delehanty said the Tuesday meeting was more of a "courtesy call." She said she wanted to further discuss a timeline for the proposed 8-year project with Mr. Winton and introduce some members of the board of trustees.

Museum of Science officials did not attend, said Mr. Winton, who is spearheading efforts to redevelop the park, now used for events such as Cirque du Soleil, concerts and a Halloween festival.

Mr. Winton said he wants officials from both museums to reduce the amount of funds they expect from the public sector.

A new Miami Art Museum is projected to cost $175 million, with about $145 million needed from the public sector, which could be a combination of local, state and federal funds, Ms. Delehanty said.

A new Museum of Science is estimated to cost $200 million, museum Chair Louise Valdes-Fauli said. She said about $150 million could come from the federal, state and local government.

Mr. Perez said that his group hopes to raise between $30 million and $35 million from private donors, but Mr. Winton was pushing hard to increase the private-sector commitment.

"He wants to see the private sector take a more aggressive role," said Mr. Perez, who is heading art museum fundraising efforts together with Mr. Cejas and Ms. Ferrell.

He said the fund-raising would take four years. The building design would start in a year and construction could begin by 2006, Mr. Perez said.

Commissioners said last year they would support having the museums in the park. They said cultural facilities would bring life to the park and the neighborhood, just as the American Museum of Natural History in Central Park does in New York, the Conservatory Balboa Park does in San Diego and the Smithsonian Institute does at The Mall in Washington, DC.

Last November, commissioners pledged $3.5 million for each museum as part of a $255 million bond referendum passed by city voters. The referendum requires a three-to-one match from each museum.

The city plans to start issuing the bonds in July. Museum officials asked Mr. Winton Tuesday if each group could start getting portions of the $3.5 million as they raise part of the $10.5 million each needs for the match instead of having to wait to raise the whole amount. Commisisoner Winton said he would endorse the early dispersement.

Separate plans call for about $17 million in bond program funds to be used for a $23 million redevelopment of Bicentennial Park, aside from construction of buildings.

Although a museum park theme has so far received the most favorable attention, commissioners will have the option to vote on two other designs, also resulting from public meetings held last year.

A second proposal calls for a park retaining more open space and adding landscape, estimated to cost up to $26 million. The other is a park with reduced green space and housing, and businesses rising at its edges, projected to cost up to $24 million.